1. Technical Field
The present invention relates to a head-mount type display device.
2. Related Art
There has been known ahead-mount type display device (a head-mounted display (HMD)) as a display device to be used in the state of being mounted on the head. The head-mount type display device generates image light representing an image using, for example, a liquid crystal display and a light source, and then guides the image light thus generated to the eyes of the user using a projection optical system and a light guide plate to thereby make the user visually recognize a virtual image.
JP-A-2002-125137 (Document 1) discloses a device capable of operating the head-mount type display device by remote control. When a predetermined time has elapsed from when the head-mount type display device is powered ON, this device displays a message representing the fact that the head-mount type display device has been used for a long period of time to thereby call attention to the user in using the head-mount type display device.
Further, JP-A-2013-176535 (Document 2) discloses a technology capable of measuring the pulse wave while reducing an influence of a noise on a measurement signal by analyzing the fluctuation in the respective measurement signals detected by a plurality of light receiving sections in a pulse wave measurement device to be mounted on the wrist.
Further, as examples of related art documents, there can be cited the research study report on an influence of contents on a living body (March 2004, Ministry of Internal Affairs and Communications), and the guideline on an imaging technique such as animation (2006, Japan Broadcasting Corporation, The Japan Commercial Broadcasters Association).
However, in the technology described in Document 1, the control for avoiding prolonged use, such as display of a warning message or forced stop of the head-mount type display device is performed without exception when a predetermined time has elapsed regardless of the type of the content to be visually recognized by the user or the health condition of the user. Since in the related art technology, the control for avoiding prolonged use is performed without exception after the predetermined time has elapsed as described above, there is a problem that in some cases, the timing of such control is too early, or by contraries too late depending on the physical condition of the user or the individual difference between the users. It should be noted that such a problem exists not only in the control for avoiding prolonged use, but also in other control such as the control of the luminance of the image light in a similar manner.
Further, in the technology described in Document 2, although the pulse wave of the user can more accurately be detected than ever, there is a demand for using the pulse wave thus detected in controlling a variety of types of devices. Further, there is a problem that the biological information of the user other than the pulse wave also needs to be detected.